so i have a little problem, i have two engines, a 351 that im making in to a 400 for a back up engine and a built 400 for my 79 f250 4x4. i have one 4x4 oil pan and one 2x4 oil pan. what is the big difference? and why cant i used the 2x4 in mine?

 

oil sumps...front sump vs. rear sump...front sump oil pan comes in contact w/ front differential!

 

if you have very much lift at all on your truck you will probably never hit the oil pan with your differential. If you have stock suspension and wheel hard you MIGHT hit it.

 

You will hit it if you are stock, but I have seen one that was smashed to sh** and didn't leak.

 

on a half ton it is very possible that you would hit it. I know a guy with a 79 f-250 (same as yours) with stock suspension and a front sump pan that has never hit his chasing coyotes, although it was already dented from being in a half ton, and I did BARELY hit mine in a stock f-350 once, but i guess these were both 460 trucks. maybe a 351m/400 pan is different and more likely to hit, but i would doubt it, especially with normal driving.

 

Not to mention that you do want your oil pick up at the back in a 4x4 if you are climbing any hills, going down hill you would most likely be at a low rpm.

 

Your 351 or 400 is lighter than a 460, same springs in a F250, so there's a chance no hitting. If there's a motor in the truck, measure from lowest edge of block to axle at resyt and compare to travel remaining at frame bump stops, allowing for compression of stops of course. What is left is how much room you have for oil pan.

OK in normal use but really steep inclines is where that full bodied 7 quart 4x4 pan and "rear-middle" sump helps.